A measuring sensor device 1 for detecting a physical quantity which, via a physical electrical transducer 2, is converted into an equivalent analog electrical quantity and, by means of an analysis circuit 5 connected behind it, which constructionally is not combined with the measuring sensor device 1, is connected to this measuring sensor device 1 by way of electrical lines (Lm1, Lm2, +Us, -Us) used for the transmission of measured values and/or for the energy supply of the measuring sensor device, is converted into quantities, preferably digital data which can be processed further (measuring operation), the physical-electrical transducer 2 being connected in a bridge circuit (measuring bridge 3), and individual branches of the measuring bridge 3, for calibration purposes, being capable of being detuned in a defined manner by the parallel connecting of a shunt resistor (Rs) arranged on the measuring sensor device 1, by way of switches (shunt switches S1, S2) assigned to the analysis circuit 5 and a shunt line Lsh connecting the switches with the shunt resistor (shunt calibration, calibrating operation), and an identification generator 8 being integrated in the measuring sensor device 1 which comprises a nonvolatile memory module 9, 18 with correction data (sensor identification data) of the measuring sensor device 1, as well as a controllable switching element (sh+, sh-) situated in parallel to a branch (R2, R4; R1, R3) of the measuring bridge 3, for the defined detuning of the measuring bridge 13 in the controlled condition, the identification generator 8, in the case of an activatable transmission of the correction data to the analysis circuit 5, switching the controllable switching element (Sh+, Sh-) on and off in the rhythm of the data bit flow read out serially from the memory module 9, 18, and the analysis circuit 5 or a computer connected behind it detecting the analog signals or their changes at the measuring bridge 3 and regenerating the correction data from them which may be used for the correction of the electrical quantities furnished by the physical-electrical transducer 2 (identifying operation), characterized in that, from the identification generator, at least one auxiliary shunt resistor (Rsh+, Rsh-), by way of electrically controllable auxiliary shunt switches (Sh+, Sh-), can be connected in parallel to at least one of the switches (S1, S2) and the shunt resistor (Rs), and in that the identification generator 8 has a circuit 20 which responds to defined pulses or a defined pulse sequence on the shunt line (Lsh) and controls the identification generator 8, and the identification generator 8 can be switched over in its operating mode (measuring operation, calibrating operation) by the superimposing of such pulses or pulse sequences on the shunt line (Lsh) by means of the shunt switches (S1, S2), in the operating mode.
--measuring operation and calibrating operation, the identification generator 8 being switched in such a manner that the measuring sensing is largely unaffected by the identification generator 8, PA1 --calibrating operation, the physical-electrical transducer 2 can be detuned in a defined manner by the shunt switches (S1, S2; Sh+, Sh-) and the shunt resistor (Rs; Rsh+, Rsh-), PA1 --identifying operation, by controlling the auxiliary shunt switches (Sh+, Sh-) by means of the controlling circuit 20, the correction data can be transmitted via the measuring lines (Lm1, Lm2) from the identification generator 8 to the analysis circuit.
In measuring devices or measuring data detecting and processing systems, it is frequently necessary to place the measuring sensor device with the actual physical-electrical transducer, which detects a physical quantity to be detected and converts it into an electric signal which is equivalent to it, physically away from an analysis circuit for the signal (or measured value) editing and processing. The measuring sensor device and the analysis circuit are then as a rule connected with one another by way of electric lines, the lines, in turn, being connected with the analysis circuit of a plug connection.
The separation of the measuring sensor device and the analysis circuit is frequently for reasons related to space (in order to be able to construct the measuring sensor device as small as possible). However, it is often the result of a "rough" environment in which the measuring device is to be operated. These are frequently extremely high or low temperatures, dirt, humidity, high electromagnetic radiation, etc., which are conditions under which the measuring sensor devices can operate more or less perfectly, but in which the operatability of an analysis device with sensitive electronic components does not exist.
German Patent Document DE-34 46 248 A1 shows a measuring sensor device is known with a physical-electrical transducer which constructionally is not combined with an analysis circuit. The measuring sensor device comprises a memory module with correction data for the measured values detected by the physical-electrical transducer. The physical-electrical transducer and the memory module are connected by way of at least one output with the analysis circuit which can read the correction data out of the memory module and correspondingly correct the measured values supplied by the transducer.
However, this known measuring sensor device and the process for its alignment show only a principle for the method of operation of such a measuring system but supply no information with respect to a technical implementation in practice. In addition, a programming of the memory module with the correction values requires a connecting of a plurality of lines (bus connection) which, when the sensor is completed, are no longer accessible from the outside so that an "aged" measuring sensor device (that is, a measuring sensor device which no longer furnishes correct data) can no longer be recalibrated. The measuring sensor must therefore be replaced.
Likewise, German Patent Document DE-33 18 977 A1 discloses a measuring sensor device with an information carrier (memory module) which contains operating data. Data of the memory module are either read out at the start of the operation via several connecting lines which are separated from the measuring lines and are transmitted to a remotely arranged microcomputer, or the whole memory module is removed and inserted into a processing part which operates away from the sensor.
Thus, either additional lines are required from the sensor to the processing part, or a manual operation is required which, on the one hand, is cumbersome and, on the other hand, may frequently result in damage to the sensitive connecting contact pins of the memory module.
A device for the measuring of physical quantities comprising a digital memory is shown in German Patent Document DE 31 16 690 A1. This digital memory can be loaded with calibration data for the device. However, for the readin/readout of data from this digital memory, special electric connecting lines must be provided which connect the device with an analysis device in addition to the measuring and power supply lines.
German Patent Document DE-37 43 846 A1 comprises a measuring sensor device with a memory module which is a component of an identification generator integrated in the measuring sensor device. For the initialization of the readout process, the identification generator is acted upon via only one other line with a timing signal which is used at the same time for the timing synchronization and the power supply of the identification generator. During the readout process, the data are fed, by means of the coupling of the identification generator, to the lines which are normally used for the measured-value transmission, to an analysis circuit with analog inputs and are regenerated there from the signals present on the lines or from their changes.
Furthermore, measuring sensor devices with physical-electrical transducers are known in the case of which, for the purpose of calibration, by way of a shunt switch, a shunt resistor can be connected in parallel with respect to bridge branches (shunt calibration).
An object of the invention is to integrate into a measuring sensor device with a shunt calibration an identification generator so that, with as few expenditures as possible with respect to additional components or lines, a controlled readout of data from a memory of the identification generator becomes possible as well as their transmission to an analysis circuit.
Some of the principal advantages of the invention are that a measuring sensor device with a correction data memory module is provided from which the correction data can be read out by simple devices when the operation of the measuring sensor device is started because, for this readout process, largely existing lines are used which are normally used for the measured-value transmission or the power supply or a shunt calibration of the sensor.
The circuit (identification generator) to be arranged for this purpose in the measuring sensor device is distinguished by a small number of switching elements and negligibly affects the measured-value detection in the measuring operation. The identification generator is also distinguished by a high operating temperature range. Furthermore, in the case of a calibration or recalibration, data can be written in via the existing lines from the analysis circuit into the memory module of the measuring sensor device.
Another advantage provided by the identification generator, of the present invention is the possibility of filing operational data of the measuring sensor device, such as the supply voltage and the site of application, in the memory module and reading them out because the identification generator can be operated completely independently of the actual sensor (physical-electrical transducer).
By means of counting pulses superimposed on the shunt line and by means of a circuit which counts them in the identification generator, the identification generator of the present invention can be switched with respect to its mode of operation (measuring operation, calibrating operation, identifying operation), and the initialization and the control of the data transmission can be influenced so that the data output can be adapted to the most varied analysis circuits or a starting address for the readout of the data from the memory module can be changed.